Production of propionic acid through biotransformation of glucose and d-lactic acid by construction of synthetic acrylate pathway in metabolically engineered E. coli

A Veillonella species and Enterococcus durans were isolated from the cecal contents of adult broilers. Mixed cultures of Veillonella and E. durans inhibited the growth of Salmonella typhimurium and Escherichia coli 0157:H7 on media containing 2.5% lactose (w/v). The growth of S. typhimurium or E. coli 0157:H7 was not inhibited by mixed cultures containing Veillonella and E. durans on media containing only 0.25% lactose or by pure cultures of Veillonella or E. durans on media containing either 0.25% or 2.5% lactose. The mixed cultures of Veillonella and E. durans produced significantly (P<0.05) more acetic, propionic, and lactic acids in media containing 2.5% lactose than in media containing 0.25% lactose. The inhibition of the enteropathogens was related to the production of lactic acid from lactose by the E. durans and the production of acetic and propionic acids from lactic acid by the Veillonella.

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Inactivation of Escherichia coli O157:H7, Salmonella enterica Serotype Enteritidis, and Listeria monocytogenes on Lettuce by Hydrogen Peroxide and Lactic Acid and by Hydrogen Peroxide with Mild Heat

Journal of Food Protection ◽

10.4315/0362-028x-65.8.1215 ◽

2002 ◽

Vol 65 (8) ◽

pp. 1215-1220 ◽

Cited By ~ 107

Author(s):

CHIA-MIN LIN ◽

SARAH S. MOON ◽

MICHAEL P. DOYLE ◽

KAY H. McWATTERS

Keyword(s):

Escherichia Coli ◽

Hydrogen Peroxide ◽

Lactic Acid ◽

Listeria Monocytogenes ◽

Salmonella Enterica ◽

Salmonella Enteritidis ◽

Sensory Characteristics ◽

Escherichia Coli O157 ◽

E Coli ◽

Log Reduction

Iceberg lettuce is a major component in vegetable salad and has been associated with many outbreaks of foodborne illnesses. In this study, several combinations of lactic acid and hydrogen peroxide were tested to obtain effective antibacterial activity without adverse effects on sensory characteristics. A five-strain mixture of Escherichia coli O157:H7, Salmonella enterica serotype Enteritidis, and Listeria monocytogenes was inoculated separately onto fresh-cut lettuce leaves, which were later treated with 1.5% lactic acid plus 1.5% hydrogen peroxide (H2O2) at 40°C for 15 min, 1.5% lactic acid plus 2% H2O2 at 22°C for 5 min, and 2% H2O2 at 50°C for 60 or 90 s. Control lettuce leaves were treated with deionized water under the same conditions. A 4-log reduction was obtained for lettuce treated with the combinations of lactic acid and H2O2 for E. coli O157:H7 and Salmonella Enteritidis, and a 3-log reduction was obtained for L. monocytogenes. However, the sensory characteristics of lettuce were compromised by these treatments. The treatment of lettuce leaves with 2% H2O2 at 50°C was effective not only in reducing pathogenic bacteria but also in maintaining good sensory quality for up to 15 days. A ≤4-log reduction of E. coli O157:H7 and Salmonella Enteritidis was achieved with the 2% H2O2 treatment, whereas a 3-log reduction of L. monocytogenes was obtained. There was no significant difference (P > 0.05) between pathogen population reductions obtained with 2% H2O2 with 60- and 90-s exposure times. Hydrogen peroxide residue was undetectable (the minimum level of sensitivity was 2 ppm) on lettuce surfaces after the treated lettuce was rinsed with cold water and centrifuged with a salad spinner. Hence, the treatment of lettuce with 2% H2O2 at 50°C for 60 s is effective in initially reducing substantial populations of foodborne pathogens and maintaining high product quality.

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Growth, Inhibition, and Survival of Listeria monocytogenes as Affected by Acidic Conditions

Journal of Food Protection ◽

10.4315/0362-028x-53.8.652 ◽

1990 ◽

Vol 53 (8) ◽

pp. 652-655 ◽

Cited By ~ 72

Author(s):

DONALD E. CONNER ◽

VIRGINIA N. SCOTT ◽

DANE T. BERNARD

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Growth Inhibition ◽

Propionic Acid ◽

Cell Populations ◽

Growth And Survival ◽

Viable Cells ◽

Acidic Conditions ◽

Ph Range ◽

Lactic Acids

Growth and survival of four strains of Listeria monocytogenes under acidic conditions were investigated. Tryptic soy broth with yeast extract (TSBYE) was acidified with acetic, citric, hydrochloric, lactic, or propionic acid to pH 4.0–6.0, inoculated with L. monocytogenes and incubated at 30 or 4°C. The minimum test pH at which L. monocytogenes did not grow (inhibitory pH) was determined for each acid. In the pH range tested, this inhibitory pH was 5.0 for propionic acid, 4.5 for acetic and lactic acids, and 4.0 for citric and hydrochloric acids. All four strains gave similar results. Subsequent studies were conducted at 10 and 30°C to determine changes in cell populations in TSBYE adjusted to each inhibitory pH. Initial populations of viable cells (104 CFU/ml) were reduced to <10 CFU/ml within 1–3 weeks at 30°C, whereas at 10°C, L. monocytogenes survived for 11–12 weeks in acetic, citric, or propionic acid-adjusted media and for 6 weeks in media adjusted with hydrochloric or lactic acid. The concentration of undissociated lactic acid was 0.002 M at pH 4.5.

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A Clean-In-Place Type Sanitation Method Validation for a Benchtop Meat Grinder

Meat and Muscle Biology ◽

10.22175/mmb.10732 ◽

2019 ◽

Vol 3 (2) ◽

Author(s):

C. E. Rayfield ◽

R. Jadeja ◽

S. Billups

Keyword(s):

Lactic Acid ◽

Foodborne Pathogens ◽

Peracetic Acid ◽

Deionized Water ◽

Cross Contamination ◽

Direct Plating ◽

Water Ice ◽

E Coli ◽

Different Types ◽

Low Levels

ObjectivesThis research is designed to validate a novel clean-in-place type antimicrobial ice-based meat grinder sanitation method.Materials and MethodsFour different types of antimicrobial ice were prepared from peracetic acid (PAA, 350 mg/L) and combination PAA with 2% FreshFX® (PAAF), 2% Paradigm® (PAAP) and 2% lactic acid (PAAL). The grinders were inoculated by processing 400 g beef trim containing 400 μL of E. coli O157:H7 or S. Typhimurium DT 104 suspensions at 8.4 to 8.7 (high inoculation) and 5.3 to 5.5 (low inoculation) log CFU/mL. Each meat grinder was then treated by processing 1000 g of antimicrobial ice and 500 mL of corresponding antimicrobial solution. At the end of each treatment, 400 g un-inoculated beef was processed through the meat grinder, and the resulting ground beef was then analyzed for the presence of target pathogens by direct plating and after enrichment. Efficacies of antimicrobial ice-based treatments were compared with 1000 g deionized water ice + 500 mL deionized water (DI), and no treatment (NT) controls.ResultsAll antimicrobial ice treatments were able to reduce cross-contamination to non-detectable levels from the meat grinders inoculated at the low levels of pathogens, but after enrichment, target pathogens were detected in all the samples. Recoveries from the meat grinder inoculated with high levels of pathogens ranged from 5.95 to 3.50 log CFU/g and 5.86 to 3.46 log CFU/g for E. coli O157:H7 and S. Typhimurium DT 104, respectively. All antimicrobial ice treatments were significantly (p ≤ 0.05) more effective in reducing cross-contamination in comparison of NT and DI controls. The microbial reductions achieved by different antimicrobial ice treatments were not significantly (p ≤ 0.05) different from each other.ConclusionThe antimicrobial ice-based meat grinder sanitation technique could effectively reduce foodborne pathogens from meat grinders without needing meat grinder disassembly.

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Lactic Acid Bacteria (Lactobacillus bulgaricus and Streptococcus thermophillus) in Yogurt Inhibit the Growth of Escherichia coli, Salmonella typhimurium, and Shigella sp. In Vitro

Jurnal Kedokteran Brawijaya ◽

10.21776/ub.jkb.2021.031.04.2 ◽

2021 ◽

Vol 31 (4) ◽

pp. 2

Author(s):

IDSAP Peramiarti

Keyword(s):

Escherichia Coli ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Salmonella Typhimurium ◽

Pathogenic Bacteria ◽

Test Method ◽

P Value ◽

E Coli ◽

Significant Difference

Diarrhea is defecation with a frequency more often than usual (three times or more) a day (10 mL/kg/day) with a soft or liquid consistency, even in the form of water alone. Pathogenic bacteria, such as Escherichia coli, Salmonella typhimurium, and Shigella sp., play a role in many cases, to which antibiotics are prescribed as the first-line therapy. However, since antibiotic resistance cases are often found, preventive therapies are needed, such as consuming yogurt, which is produced through a fermentation process by lactic acid bacteria (LAB). This research aimed to determine the activity of lactic acid bacteria (Liactobacillus bulgaricus and Streptococcus thermophilus) in yogurt in inhibiting the growth of the pathogenic bacteria E. coli, S. typhimurium, and Shigella sp. The research applied in vitro with the liquid dilution test method and the true experimental design research method with post-test-only and control group design. The design was used to see the inhibitory effect of yogurt LAB on the growth of E. coli, S. typhimurium, and Shigell sp. to compare the effect of several different yogurt concentrations, namely 20%, 40%, 60%, and 80%. The results of the Least Significance Different analysis showed that there was a significant difference between yogurt with a concentration of 0% and that with various concentrations in inhibiting the growth of E. coli, S. typhimurium, and Shigella sp. with a p-value of <0.05. Whereas, there was no significant difference in the various concentrations of yogurt in inhibiting the growth of the three kinds of bacteria with a p-value of > 0.05.<p class="Default" align="center"> </p>

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Viability of lactic acid bacteria in different components of Ogi with anti diarrhoeagenic E. coli activities

The North African Journal of Food and Nutrition Research - July-December 2021 ◽

10.51745/najfnr.3.6.206-213 ◽

2019 ◽

Vol 3 (6) ◽

pp. 206-213

Author(s):

Roseline Eleojo Kwasi ◽

Iyanuoluwa Gladys Aremu ◽

Qudus Olamide Dosunmu ◽

Funmilola A. Ayeni

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Antimicrobial Properties ◽

Culture Method ◽

Antimicrobial Activities ◽

Drying Methods ◽

Bacterial Strains ◽

E Coli ◽

Log Reduction ◽

Freeze Dried

Background: Ogi constitutes a rich source of lactic acid bacteria (LAB) with associated health benefits to humans through antimicrobial activities. However, the high viability of LAB in Ogi and its supernatant (Omidun) is essential. Aims: This study was carried out to assess the viability of LAB in various forms of modified and natural Ogi and the antimicrobial properties of Omidun against diarrhoeagenic E coli. Methods and Material: The viability of LAB was assessed in fermented Ogi slurry and Omidun for one month and also freeze-dried Ogi with and without added bacterial strains for two months. A further 10 days viability study of modified Omidun, refrigerated Omidun, and normal Ogi was performed. The antimicrobial effects of modified Omidun against five selected strains of diarrhoeagenic E. coli (DEC) were evaluated by the co-culture method. Results: Both drying methods significantly affected carotenoids and phenolic compounds. The Ogi slurry had viable LAB only for 10 days after which, there was a succession of fungi and yeast. Omidun showed 2 log10cfu/ml reduction of LAB count each week and the freeze-dried Ogi showed progressive reduction in viability. Refrigerated Omidun has little viable LAB, while higher viability was seen in modified Omidun (≥2 log cfu/ml) than normal Omidun. Modified Omidun intervention led to 2-4 log reduction in diarrhoeagenic E. coli strains and total inactivation of shigella-toxin producing E. coli H66D strain in co-culture. Conclusions: The consumption of Ogi should be within 10 days of milling using modified Omidun. There are practical potentials of consumption of Omidun in destroying E. coli strains implicated in diarrhea. Keywords: Ogi, Omidun, lactic acid bacteria, diarrhoeagenic Escherichia coli strains, Viability.

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Citric and Lactic Acid Effects on the Growth Inhibition of E. coli and S. typhymurium on Beef during Storage

Sarhad Journal of Agriculture ◽

10.17582/journal.sja/2015/31.3.183.190 ◽

2015 ◽

Vol 31 (3) ◽

pp. 183-190 ◽

Cited By ~ 4

Author(s):

Gultaj Hussain ◽

◽

Abdur Rahman ◽

Tariq Hussain ◽

Siraj Uddin ◽

...

Keyword(s):

Lactic Acid ◽

Growth Inhibition ◽

E Coli

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Antimicrobial activity of lactic acid bacteria isolated from garri on Escherichia coli strains isolated from clinical and environmental samples

Agricultural Science and Technology ◽

10.15547/ast.2020.04.057 ◽

2020 ◽

Vol 12 (4) ◽

pp. 357-365

Author(s):

H.I. Atta ◽

A. Gimba ◽

T. Bamgbose

Keyword(s):

Escherichia Coli ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Lactobacillus Plantarum ◽

Lactobacillus Acidophilus ◽

Plant Pathogens ◽

Resistant Bacteria ◽

Fermented Foods ◽

Environmental Isolates ◽

E Coli

Abstract. The production of bacteriocins by lactic acid bacteria affords them the ability to inhibit the growth of bacteria; they are particularly important in the biocontrol of human and plant pathogens. Lactic acid bacteria have been frequently isolated from fermented foods due to the high acidity these foods contain. In this study, lactic acid bacteria were isolated from garri, a popular Nigerian staple food, which is fermented from cassava, and their antagonistic activity against clinical and environmental isolates of Escherichia coli was determined. The species of Lactobacillus isolated include: Lactobacillus plantarum (50%), Lactobacillus fermentum (20%), Lactobacillus acidophilus (20%), and Lactobacillus salivarius (10%). Growth inhibition of the strains of E.coli was observed in Lactobacillus plantarum that inhibited the growth of both. The clinical and environmental isolates of E. coli were inhibited by Lactobacillus plantarum, while Lactobacillus acidophilus showed activity against only the clinical isolate. The greatest zone of inhibition against the strains of E. coli was recorded by Lactobacillus acidophilus (22.7±1.53 mm). The bacteriocins produced by Lactobacillus species have a good potential in the biocontrol of pathogens, and should be the focus of further studies on antibiotic resistant bacteria.

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Microbiological Condition of Retail Beef Steaks: A Canadian Survey

Journal of Food Research ◽

10.5539/jfr.v7n4p1 ◽

2018 ◽

Vol 7 (4) ◽

pp. 1 ◽

Cited By ~ 3

Author(s):

Xianqin Yang ◽

Julia Devos ◽

Hui Wang ◽

Mark Klassen

Keyword(s):

Escherichia Coli ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Microbial Quality ◽

Indicator Organisms ◽

Mean Values ◽

E Coli ◽

Upper Limit ◽

Brochothrix Thermosphacta ◽

Beef Steaks

The second national baseline microbiological survey of beef steaks offered for retail in Canada was conducted in 2015. A total of 621 steaks of four types (cross rib, CR; inside round, IR; striploin, SL; top sirloin, TS) collected from 135 retail stores in five cities across Canada were tested. Swab samples each from swabbing the entire upper surface of each steak were processed for enumeration of seven groups of indicator organisms: total aerobes (AER), psychrotrophs (PSY), lactic acid bacteria (LAB), pseudomonads (PSE), Brochothrix thermosphacta (BRO), coliforms (COL) and Escherichia coli (ECO). The overall mean values (log CFU/100 cm2) were 5.17±1.29, 4.92±1.36, 4.79±1.42, 3.26±1.49, 2.34±1.88, and 0.80±1.05 for AER, PSY, LAB, PSE, BRO, and COL, respectively. ECO were not recovered from 87.3% of the steaks and when there was recovery, the numbers were mostly ≤ 1 log CFU/100 cm2. Strong correlation was found between the log numbers of AER and PSY, of AER and LAB, and of PSY and LAB, while the correlation between the log numbers of COL and ECO was weak. The numbers of COL and ECO from different groups of steak types or from different cities were not substantially different. Of the four types of steaks, IR had the lowest median values for AER, PSY, LAB, PSE and BRO, followed by CR. The microbiological condition of retail beef steaks in this survey was on par with that in the previous one, with very low numbers of generic E. coli being recovered from very few steaks and the indicators for microbial quality being at numbers much lower than the upper limit for shelf life of beef.

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